Possible Breakthrough in Energy Storage
Gary Tulie writes: Hi Craig, This could be big. An ultracapacitor made of low-cost non-toxic materials with energy density as good as lithium ion batteries, with many times the charge and discharge rate.
Yes, this sounds like it really could be huge.
For those new to the subject, capacitors and batteries both store electrical energy, but in two different ways. Batteries are based on chemical reactions that cause electrons to flow in a certain direction; capacitors (as illustrated above) are simply a pair of conductors that are separated by a physical insulator. As such, they have different characteristics that make them better or worse suited to perform certain tasks.
In all, there are several parameters that enter the discussion, as follows:
Gravimetric energy density: The total energy that can be stored per kilogram
Volumetric energy density: The total energy that can be stored per liter
Gravimetric power density: The energy per second that can be transferred per kilogram
Volumetric power density: The energy per second that can be transferred per liter
On top of this, we have to layer cost. For example, stationary storage devices can be bigger and heavier that those that move around. When you look under the hood of a car that was built in the last 20 years, you notice that every cubic inch has a purpose. And needless to say, removing weight from our cars is even more important. Conversely, we are far less concerned about the size and weight of a battery in our garage that may store solar energy for use at night, or off-peak energy for use at peak times.
Primarily, capacitors generally have much larger power densities (both gravimetric and volumetric) than batteries, meaning that they can deliver energy faster than batteries of equal size and mass. This, obviously, is a big deal in electric transportation, where we need to accelerate a mass of thousands of kilograms from a dead stop to freeway speed fairly quickly.
Yet at the same time, energy density is the thing that keeps the vehicle moving mile after mile; low energy density means short ranges = range anxiety = consumer rejection. For this reason, we often hybridize electric drive trains with both batteries and capacitors.
Again, however, it all comes down to cost, which is what makes the announcement in the article linked above so exciting.
Great time to be alive.
Gary,
For decades, nearly a century, the prospect of ultra-capacitors being able to store and discharge power intermittently, with density and over a lengthy time period has been the challenge for engineers and scientists.
It’s a challenge that never failed to fascinate me. Over the years I’ve followed hundreds of announcements, reviewed thousands of eager promoters of ‘almost ready’ projects with a view to commercialization, but none have ever shown any more than promise.
I wish all researchers in this field well and look forward to news of a breakthrough with eager anticipation. However, I agree with Craig, these announcements should be treated with circumspection and not interpreted as occurring in the near future.
Still, it’s exciting…..